[vsnet-grb-info 19649] GRB 170728B: BOOTES-2/TELMA optical detection during the extended gamma-ray phase

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21393
SUBJECT: GRB 170728B: BOOTES-2/TELMA optical detection during the extended gamma-ray phase
DATE:    17/07/30 17:00:39 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct at iaa.es>

A. J. Castro-Tirado (IAA-CSIC Granada & ISA-UMA Málaga), A. 
González-Rodríguez, Y. Hu, R. Cunniffe, J. C. Tello, B.-B. Zhang 
(IAA-CSIC Granada), A. Castellón, I. Carrasco (UMA Málaga), M. Jelínek 
(ASU-CAS Ondrejov), S. Guziy (Nikolaev Univ.), S. B. Pandey (ARIES 
Nainital), S. Jeong (SKKU Seoul), M. D. Caballero-García (ASU-CAS 
Prague), M. Wildi (Vermes Obs.) and P. Kubánek (IP-ASCR Prague), on 
behalf of a larger collaboration, report:

Following the detection of GRB 170728B by Swift (Cenko et al. GCNC 
21371), the TELMA 0.6m robotic telescope at the BOOTES-2 astronomical 
station at IHSM/UMA-CSIC in Málaga (Spain) pointed to the GRB location 
26 sec after the notice time and 40 sec after trigger time, i.e. at 
23:03:59 UT on July 2.

The first exposures (3 sec, unfiltered) were taken simultaneously to the 
extended gamma-ray emission phase (Stanbro et al. GCNC 21383, Ukwatta et 
al. GCNC 21384), confirming the optical transient within the Swift/XRT 
error box (D'Elia et al., GCNC 21376) being coincident with the optical 
afterglow position (D'Avanzo et al. GCN 21373) with magnitudes in the 
range reported by Lipunov et al. (GCNC et al. 21391) starting 2 sec 
after. A detailed analysis is ongoing.

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